Study participants applied a single dose of tenofovir gel two hours before birth by cesarean section.
Dr Richard Beigi of the University Pittsburgh and Magee-Women’s Hospital, who headed the study for the Microbicide Trials Network (MTN), said it microbicides could be an integral part in the prevention arsenal since there was evidence that condom use decreased during pregnancy.
Women in the study were discouraged from falling pregnant while participating in the trial and encouraged to use birth control and condoms.
Tenofovir, a widely used antiretroviral, was one of the compounds used in the candidate microbicide.
Previous research has shown that tenofovir is safe and effective for use in pregnant women.
However, earlier research showed that oral ingestion of tenofovir led to small amounts of the drug being passed onto the baby when given to women to prevent HIV transmission to their babies during birth.
The microbicide study showed that the levels of tenofovir found in the umbilical cord were 40 times lower than levels found when the drug was applied orally.
The mothers and babies suffered no serious side effects due to the gel, researchers said.
Beigi said the findings supported continuing studies that used tenofovir gel among pregnant women.